1. Field of the Invention
The present invention relates to an active material, an electrode including the active material and a manufacturing method thereof, and a secondary battery.
2. Description of the Related Art
In recent years, with the advance of environmental technology, development of power generation devices (e.g., solar power generation devices) which pose less burden on the environment than conventional power generation methods has been actively conducted. Concurrently with the development of power generation devices, development of power storage devices has also been underway.
As an example of a power storage device, a lithium ion battery can be given. Lithium ion batteries have been widely used because they have high energy density and are thus suitable for reduction in size. As a negative electrode material of a lithium ion battery, a material in/from which lithium ions can be inserted and extracted is preferably used. Although graphite, silicon, and the like can be given as examples of such a material, silicon is especially preferred. This is because silicon has about ten times as high theoretical capacity as graphite and thus is expected to be a host material of lithium (e.g., Patent Document 1).